Industrial robots are in widespread use for automated industrial painting and coating operations. Automation of interior painting or coating is limited by the difficulties experienced in locating a panel, such as a hood/deck or door panel, without damaging the panel. Further difficulties are experienced in holding a panel in position once located.
A newly manufactured automobile body is typically painted with the doors installed. During the coating process, the doors are moved from a closed position to an open position to facilitate the painting of an interior of the automobile body. The doors are returned to the closed position when the painting of the interior of the automobile body is completed. Robotic devices featuring a specially adapted tool disposed at the end of an articulated arm are typically employed to grip the doors during the opening and closing process. The automobile hood and deck can also be installed on the automobile body and must also be opened and closed during the coating process, similar to the doors.
Many automobile manufacturers paint the interior of vehicles on moving line conveyor systems. Engaging the body panels on a moving part requires design consideration for line stoppages. The panels are often kept in the closed position with production aids to keep them from opening during conveyance through the paint shop. Force transducers, breakaway devices or spring loaded complaint switch devices, such as safety clutches, have been used to detect abnormalities in the opening and closing process. These devices are used to prevent damage to the car, robot engagement tooling, and/or the robot itself during the opening, holding and closing process. Sensors are also built into the engagement tooling to detect that the panel is in the proper grasp of the device.
One such method is illustrated in U.S. Pat. No. 4,498,414 to Kiba, et al., issued Feb. 12, 1985, teaches a robot comprising a painting arm equipped with a non-contact door sensor that detects the window groove by measuring reflection time of an ultrasonic wave.
U.S. Pat. No. 4,552,506 to Cummins, et al., issued Nov. 12, 1985, for an OPENER MECHANISM and SYSTEM UTILIZING SAME that teaches an apparatus and method for opening and closing body panels of a vehicle using a mechanical four-bar linkage.
U.S. Pat. No. 4,702,666 to Iwao, et al., issued Oct. 27, 1987, teaches a manually applied door lock device for mounting on a vehicle door that opens the door to a predetermined angle.
U.S. Pat. No. 4,988,260 to Kiba, et al., issued Jan. 29, 1991, teaches an engaging rod fitted to the end of a coating robot arm. The rod is equipped with an optical or ultrasonic sensor mounted near the engaging rod.
U.S. Pat. No. 5,653,805 to Russell, et al. issued Aug. 5, 1987, teaches mechanical means for positioning a body panel during a coating process.
U.S. Pat. No. 6,375,100 to Tsaii, et al., issued Apr. 23, 2002, teaches a positioning device including an attachment structure 60, a rod 62, a flange assembly 64 and an engagement mechanism 66 for engaging a windowsill, for example, within a groove of rotatable flange 120 of the flange assembly 64.
U.S. Pat. No. 6,398,871 to Hur, issued Jun. 4, 2002, teaches a painting robot provided with a door opening/closing jig. This mechanical device eliminates the need for a separate door opening/closing robot.
U.S. Pub. No. 20070017081 to Becker, et al., issued Jan. 25, 2007, teaches a method for precisely aligning an add-on part using sensors.
The use of tooling hooks attached to hoods, hatches and desk lids is also known. For example, JP 6107252A teaches the use of a proximity switch on the ascertaining device 90 located at the end of a finger 16 that is attached to the hand of a vertical articulated robot.
JP 63106189 teaches a coating robot 16 and door on-off robot 20 installed on a traveling device on either side of a conveyor 12. A door on-off controller 36 controls each operation of the travel driver 24 for each robot. The reliability of a door opener is improved by detecting a door position with a door sensor and comparing with a reference closing door position, providing correction to the claw engaging position if necessary.
KR20040003831 teaches a displacement sensor 1 located at one end of a robot 4 for detecting the position accuracy of a fender. A hook shaped hood-opening unit 2 opens the hood to mount a hood assembly to a body 3. A robot SLC 5 inputs a position value of the fender and a fender fixing device fixes the fender panel to mount the pane to the body. A servo motor moves the fender mounting jig to a pre-determined position based on the position value.
WO 2006/035259 teaches combining a non-contact door sensor with force sensors for detecting forces on the door opening robot.
There is a continuing need for a system and method for automated interior painting or coating that eliminates the need for the sensors and breakaway devices. Desirably, the system and method reduces costs and exhibits an improved reliability over known painting systems and methods.